Vertically adjustable platform for scaffolding

ABSTRACT

A vertically adjustable work platform which may be easily attached to a conventional scaffolding or other similar supporting structure. The platform includes a spaced pair of supporting vertical trackways, each of which slidably mounts a platform bracket having a horizontal supporting member for supporting the platform therebetween and is preferably formed in sections of a length corresponding to the height of a scaffold section. A cable is releasably connected to the associated trackway, and a cable hoist is operatively connected to the cable and bracket for supporting and raising and lowering the bracket. A releasable safety brake is provided for each trackway and bracket, and includes a plurality of vertically spaced abutments positioned along the length of the trackway and a pivotal brake bar which is adapted to engage behind one of the abutments to preclude downward movement of the bracket along the trackway.

United States Patent [72] Inventor Harold R. Johnson P.0. Box 849, Monroe, N.C. 28110 [21 Appl. No. 870,457 [22] Filed Oct. 15, 1969 [45] Patented Oct. 5, 1971 [54] VERTICALLY ADJUSTABLE PLATFORM FOR SCAFFOLDING 22 Claims, 10 Drawing Figs. s2 u.s.c| 182/146' 51 1nt.Cl 1104,;1/20 501 Field 6: Search 182/145,

3,071,205 l/l963 Beck 182/146 Primary Examiner-Reinaldo P. Machado Attorney-Patron, Bell, Seltzer, Park & Gibson ABSTRACT: A vertically adjustable work platform which may be easily attached to a conventional scaffolding or other similar supporting structure. The platform includes a spaced pair of supporting vertical trackways, each of which slidably mounts a platform bracket having a horizontal supporting member for supporting the platform therebetween and is preferably formed in sections of a length corresponding to the height of a scaffold section. A cable is releasably connected to the associated trackway, and a cable hoist is opcratively connected to the cable and bracket for supporting and raising and lowering the bracket. A releasable safety brake is provided for each trackway and bracket, and includes a plurality of vertically spaced abutments positioned along the length of the trackway and a pivotal brake bar which is adapted to engage behind one of the abutments to preclude downward movement of the bracket along the trackway.

25 a as i 28 1 22 i g 2"! 2i i! Z I l J/ .12. 4s 4o PATENTED um 5 Ian SHEET 1 [IF 3 N w M H E. R b a m H 29. r 94 M Q/ ,fidq M 0% ATTORNEYS PATENTED um 51971 SHEET 2 [IF I as; 44 L 9% 9 92 l AROLbRJOHNSO tfi 4 4 egws ATTORNEYS VERTICALLY ADJUSTABLE PLATFORM FOR SCAFFOLDING The present invention relates to a vertically adjustable work platform, and more particularly, to a work platform which may be quickly and easily attached to a supporting structure such as a sectional scaffold of conventional design for free, unobstructed vertical movement therealong.

Scaffolding of the type with which the present invention is particularly concerned is extensively employed in the building industry to support workmen and materials along a work area. Typically, the scaffolding is used to assist in the erection of masonry walls or the like wherein the laying of bricks, blocks or tiles progressively increases the height of a wall. To this end, the scaffolding generally includes a plurality of substantially identical sections which are adapted to be placed in parallel upright relation along the work area to form a first level. Additional levels may be superposed above the first level whereby the height of the scaffolding may be increased as the work progresses and the men and materials will always be supported at not too inconvenient heights. Each section comprises a pair of interconnected parallel spaced uprights, usually 4 to 7 feet in height, and the various sections are interconnected by diagonal connecting braces to form a continuous structure.

In accordance with one aspect of the present invention, there is provided a sectional scaffold of the above type having a platform structure connected thereto in a manner to permit the platform to be progressively elevated or lowered over the entire height of the scaffold without obstruction by the connecting braces and without the necessity of removing these braces.

While scaffolds with platforms of this general type are known in the art, prior designs universally require that the diagonal braces between the vertical sections on the front side of the scaffold be either permanently removed or temporarily removed and replaced as the platform moves along the scaffold sections. In the latter case, movement of the platform is a time consuming operation since the braces of the scaffold must be disconnected and then reconnected. In the former case, the scaffold will be significantly weakened and thus the safety of the workmen may be jeopardized.

Also, such prior designs usually require that the entire height of scaffolding be erected before the work is commenced and the vertically adjustable platform is mounted thereon. This is a very undesirable feature since more scaffolding is required and the skilled workmen are idle while unskilled workmen are setting up the scaffolding.

It is accordingly an object of the present invention to provide a sectional scaffold having platform structure which may be freely moved vertically relative to the scaffold sections and which does not require the removal of any of the support braces on the scaffolding. In this regard, it is an object to provide a vertically adjustable platform structure which may be attached to a scaffolding having diagonal braces across the front as well as the rear sides.

It is a further object of the present invention to provide a scaffolding platform which may be easily and quickly attached to a sectional scaffold and raised or lowered along the entire height of the scaffolding. Also, it is an object of this invention to provide a cable supporting structure for the platform which may be periodically disconnected and then reconnected at a higher level such that the platform may be raised onto newly added levels of the scaffolding.

These and other objects and advantages of the present invention are achieved in the embodiment illustrated herein by the provision of a vertically adjustable platform structure which includes a supporting vertical trackway and a slidably attached platform bracket whereby the bracket is translatable vertically along the height of the trackway. A cable is releasably connected between the bracket and the trackway for supporting the bracket, and a cable hoist is provided for raising or lowering the bracket. To insure that the bracket will not fall should the cable break, a releasable safety brake is preferably provided which is adapted to directly engage a portion of the trackway and thereby preclude downward movement of the bracket along the trackway. A pair of the trackways may be connected to one side of two of the upright sections of a scaffolding, with the two brackets supported outwardly of any connecting braces and serving to support a platform extending therebetween for free unobstructed vertical movement.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds, when taken in connection with the accompanying drawings, in which FIG. 1 is a perspective view of the platform of the present invention together with a supporting scaffolding,

FIG. 2 is a fragmentary side elevational view illustrating the manner in which the trackway is attached to the vertical section of the scaffolding,

FIG. 3 is a fragmentary side elevational view showing the manner in which the trackway is attached to the vertical section, and also illustrating the releasable brake,

FIG. 4 is an overhead plan view of the structure illustrated in FIG. 3,

FIG. 5 is an isometric view of the trackway and platform bracket of the present invention,

FIG. 6 is an exploded perspective view of the clip and cable hook of the present invention,

FIG. 7 is a fragmentary side elevational view illustrating the slidable connection between the platform bracket and supporting trackway,

FIG. 8 is an overhead plan view of the structure illustrated in FIG. 7,

FIG. 9 is a front elevational view of the platform of the present invention, and

FIG. 10 is a perspective view, partially broken away, showing the platform and overhead protective canopy.

Referring now more particularly to the drawings, there is illustrated therein a sectional scaffold, generally indicated at 261) (FIG. 1), and adjustable work platform, generally indicated at 21, which incorporate the features of the present invention. In the illustrated embodiment, the scaffold 20 comprises a plurality of substantially identical sections 22, each of which includes two vertical uprights 23 interconnected by a horizontal connecting member 24 at the upper end. The scaffold sections 22 may be fabricated from any conventional material, such as tubular steel, and may be welded or otherwise fabricated into the desired configuration. Diagonal connecting braces 25 extend between the sections 22 of each level of the scaffold 20 and are connectedthereto by a suitable connector, such as a conventional bolt (not shown). The scaffold sections 22 are designed such that one may be superposed above another in successive levels to increase the height of the scaffold 20 as the work progresses, with the aligned vertical uprights 23 being telescopically joined to form continuous vertical sup ports along the height of the scaffolding. The horizontal connecting members 24 of the scaffold sections 22 may be conveniently utilized as supports for material storage platforms, only one of which is shown and is indicated at 26.

The vertically adjustable platform 21 is supported by one side of the scaffold sections 22 adjacent the work area. Platform 21 includes means defining a pair of vertically extending trackways 27 detachably mounted on one side of a pair of scaffold sections 22. As illustrated in FIGS. 2-4, each trackway 27 is formed by a plurality of vertically aligned track sections 28 of a length substantially corresponding to the height of the scaffold sections and means is provided for releasably connecting the trackways 27 to the scaffold sections outwardly of the connecting braces 25 comprising a spaced pair of U-shaped connectors 29 mounted on each of the track sections 28 and each of which surrounds three sides of the vertical upright 23 of the scaffold section. A pair of bolts 30 extends through each connector 29 and behind the vertical upright 23, with one bolt being above a horizontally extending member and the other bolt below the horizontal member. By this arrangement, each trackway may be quickly and securely mounted along a vertical upright 23.

Each track section 28 preferably comprises an I-beam having spaced flanges 32, 33 and a connecting web 34 to define oppositely facing U-shaped channels, note FIG. 4. The outwardly facing surface of the flange 32 includes a plurality of closely and vertically spaced transverse abutments 36, which, in the illustrated embodiments, take a form similar in appearance to the teeth of a rack gear. Normally, the track sections 28 will have a height slightly less than the height of the associated vertical uprights such that the downward forces exerted on the trackway will be transferred to the upright, but with a substantially continuous trackway structure being formed along the continuous vertical uprights of the scaffold when the sections are superposed. It will be appreciated, however, that a single track section could extend upwardly along the uprights of two or more superposed sections.

A platform supporting bracket 40 is slidably connected to each trackway 27 outwardly of the connecting braces 25 for free, unobstructed vertical translation along the trackways. Each bracket 40 includes a vertical support member 42, a horizontal support member 44, and an angular support member 46. These members may be formed of any suitable structural material, such as tubular steel, and may be rigidly interconnected, as by welding, into the illustrated right triangular relationship. The outer end of the horizontal member 44 preferably includes a vertically directed tube 47 which is adapted to receive and retain the leg of a conventional safety guard rail (not shown).

The bracket 40 is slidably connected to the trackway by means which includes a pair of wheel supporting brackets 48 mounted in spaced relation along the vertical support 42 (FIG. As best seen in FIGS. 7 and 8, each wheel supporting bracket 48 includes a pair of parallel sideplates 50 and 51, which are connected to the vertical support 42 by bolts 52 with spacers 54 being positioned between the sideplates and the vertical support 42. The remote ends of side plates 50, 51 mount wheels 55, 56, respectively, which are rotatable about horizontal axes formed by the supporting bolts 55', 56' respectively.

In the illustrated embodiment, the two wheels are axially aligned with one of the wheels disposed in each of the trackway channels for engagement with the flanges 32, 33. A horizontally extending member 58 is secured to each sideplate immediately above each wheel and partially enters the associated trackway channel and thereby serves to prevent debris from reaching and fouling the wheel and also clears any collected debris from the channels during upward movement of the platform. Also, the members 58 are designed to permit only very limited lateral movement of the bracket 40 if the as sociated wheel should break.

In accordance with the present invention, each track section 28 preferably includes a clip 60 rigidly attached thereto.

adjacent the upper end thereof, note FIG. 6. In the illustrated embodiment, the clip 60 includes an upwardly inclined front wall 61 and an interconnecting central web 62. A cable hook 64, which is attached to one end of a cable 66, is adapted to engage the clip 60. The forward end of the hook 64 is U- shaped and includes a bifurcation at 65 which is adapted to receive the central web 62 of the clip and thereby prevent lateral movement therebetween. g

The lower end of the cable 66 is connected to a cable hoist 68 which in turn is connected to the upper end of the vertical support member 42. The hoist 68 is of conventional design, and its structural details form no part of this invention. As illustrated, the hoist includes a cable drum 70, a crank 71, and a ratchet arrangement 72, whereby the drum may be alternatively rotated by the crank in either direction.

To prevent downward movement of the bracket 40 during periods when the cable 66 is not connected to the trackway or upon failure of the hoist or breakage of the cable, a brake bar 74 is provided which is pivotally mounted adjacent the lower end of the vertical support member 42. The brake is pivotally connected to the support 42 by a pin 75 and includes a forward arm 76 which is adapted to engage and lock behind one of the transverse abutments 36 when rotated to the position shown in FIG. 3. More particularly, the brake bar 74 includes a forward arm 76 which is directed diagonally downward toward the abutments 36, and an elongated rear arm 77 directed horizontally away from the abutments. The rear arm is longer and heavier than the forward arm and therefore the forward arm will normally be biased upwardly into engagement with the abutments. During upward movement of the bracket 40, the forward arm 76 will merely ratchet over the abutments, while during downward movement the forward arm will engage and lock behind one of the abutments to arrest further movement.

To release the brake 74, a chain 78 is provided which is connected at one end to the rear arm 77 of the brake. When the chain is lifted, the brake bar 74 will be rotated out of engagement with the abutments to free the bracket 40 for downward translation.

As seen in FIGS. 5 and 10, the vertical support 42 mounts a pair of tubular umbrella or canopy supports 80 and 8]. These tubular supports are designed to removably mount supporting members 82 of an overhead protective umbrella or canopy 83. The upper support 80 includes a slot 84 which also serves as a convenient attachment means for the upper end of the chain The canopy 83 overlies the platform 21 and preferably the work area to protect the workmen and materials on the platform 21 and the work area from direct sunlight and rain. In this connection, during those periods when the workmen are not working, the platform may be lowered until the canopy rests on or is immediately above the wall or other work area to protect the same which would obviate the necessity of covering the top of the wall or other work area with plastic or other sheet material which is the current practice.

The platform 21 also includes a supporting platform member 85 carried by and extending between the pair of the brackets 40. The platform member 85 includes a pair of supporting studs 86 and an overlying floor 87. The ends of the two studs are connected to the horizontal support members 44 by means of floor brackets 89. The brackets are of substantially identical construction and each includes a rectangular, tubular portion 90 at one end to receive one end of the associated stud, and the outer end includes a U-shaped hook portion 91. As seen in FIG. 9, the remote end of the hook portion 91 includes an inwardly extending lip 92. From this construction, the hook portion will be seen to substantially surround the horizontal support member 44 while being releasable therefrom by lifting directly upward. The lip 92 of the hook portion serves as an additional safety device since it will tend to arrest downward movement of one of the brackets 40. In particular, should both the brake bar 74 and cable 66 fail on one of the brackets 40, the horizontal support 44 of such bracket would be gripped by the lip 92 of the hook portion 91 after a short fall.

To assemble and operate the adjustable platform of the present invention, two track sections 28 are mounted on uprights 23 of two spaced scaffold sections by means of the brackets 29 and bolts 30. The two platform brackets 40 are initially assembled on the associated trackways by slipping the same onto one end of the trackways either before or after mounting of the trackways on the scaffold sections. The cable 66 on each bracket 40 is then attached to the clips 60 at the upper end of the track sections. When the supporting studs 86 and floor brackets 89 are attached to the horizontal supports 44 and the floor 87 is in place, the platform 21 is ready for operation.

To lift each bracket 40 along the associated trackway, it is merely necessary to operate the crank 71 of the hoist. As the bracket is lifted, the brake bar 74 will ratchet over each of the abutments 36, as well as over any intermediate clips 60. When the proper height is reached, the brake bar 74 will automatically engage and lock behind the nearest abutment 36 to provide added protection against a fall.

To lower the platform, the ratchet mechanism of the hoist is reversed such that operation of the crank 71 will rotate the drum 70 in the opposite direction. The brake is released by lifting the chain 78 which in turn rotates the brake bar 74 away from the abutments 36. The bracket may then be lowered under the control of the hoist.

If the cable should be attached to the clip 60 of a particular track section 28 and it is desired to lift the platform above this level, it is merely necessary to engage the brake bar 74, relax the cable by operating the hoist in the downward direction, and then lift the cable hook 64 into the next higher clip 60. Upward movement may then be continued by forward'operation of the hoist. In this manner, the platform may be periodically lifted onto newly added levels of the scaffold and onto newly added track sections 28. Thus it is not necessary for the.

scaffold to extend to its final height when the platform is initially attached and when the work is commenced.

While the present invention has been illustrated in considerable detail herein, it will be appreciated that various modifications could be made without departing from the spirit of the invention. For example, the adjustable platform could be attached to scaffolding of various other conventional designs; or it could be attached to a structure other than a scaffolding, e.g. a steel post or a masonry wall. Also, the trackways could be integrally incorporated as one of the uprights of the scaffolding to thereby reduce the overall weight of the device and facilitate assembly.

in the drawing and specification there has been set forth a preferred embodiment of the invention, and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation:

What is claimed is:

1. In a sectional scaffold for supporting workmen and materials adjacent a work area comprising a plurality of substantially identical sections each comprising spaced uprights and at least one connecting member therebetween and some of which are adapted to be placed in parallel, upright relation to form a first level and others of which are adapted to be superposed above corresponding ones of the first and succeeding levels, and connecting braces extending between the sections of each level adjacent the uprights thereof; the improvement which comprises means for freely moving workmen and materials vertically relative to said scaffold sections without obstruction by said connecting braces and without the necessi' ty of removing said braces, said means comprising means carried by one side of said scaffold sections adjacent the work area and defining at least two vertically extending trackways spaced outwardly of said connecting braces,

platform means for supporting workmen and materials and comprising at least two platform brackets and a supporting platform extending between and carried by said brackets,

means mounting said brackets on said trackways with said brackets and platform disposed outwardly of said connecting braces for free, unobstructed vertical movement of said platform means relative to said scaffold sections, and

means operatively connected between said trackways adjacent the upper ends thereof and said platfonn brackets for moving said platform means vertically along said trackways.

2. The sectional scaffold as defined claim 1 further comprising releasable brake means comprising a plurality of vertically spaced abutments fixedly mounted along each of said trackways, and a brake bar pivotally attached to each of said platform brackets and adapted to engage behind one of said abutments to preclude downward movement of said brackets along said trackways.

3. The sectional scaffold as defined in claim 2 wherein said brake bar includes a forward arm directed diagonally downward toward said abutments and a rear arm directed away from said abutments, said forward arm being biased upwardly into engagement with said abutments.

4. The sectional scaffold as defined in claim 1 wherein said means for moving said platform meanscomprises a pair of cable hoists connected to said platform brackets and each including a cable and-a cable, hook carried by the upper end of said cable, and a clip fixedly mounted on each of said trackways and being releasably engaged by said clip.

5. The sectional scaffold as defined in claim 1 including means releasably connecting said trackways to one side of said scaffold sections. 7

6.-The sectional scaffold as defined in claim 5 wherein said trackway connecting means includes at least a pair of U- shaped brackets surrounding three sides of one upright of said scaffold sections and bolts mounted in said brackets and extending across the fourth side of said upright.

7. The sectional scaffold as defined in claim 1 wherein each of said platform brackets includes an outwardly extending horizontalsupport member, and said supporting platform includes an end connecting bracket overlying and substantially surrounding each support member.

8. The sectional scaffold as defined in claim 1 wherein each of said trackways comprises a plurality of vertically aligned track sections substantially corresponding in height to the height of a scaffold section.

9. The sectional scaffold as defined in claim! wherein each of said trackways comprises an l-beam having spaced flanges and a connecting web defining oppositely facing U-shaped channels, and said means mounting said brackets on said trackways comprises a pair of wheels, one of said pair being disposed in each of said channels for engagement with at least one of said flanges. 1

10. The sectional scaffold as defined in claim 9 wherein a horizontally extendingmernber is attached to said bracket immediately above each of said wheels, said members partially entering the associated channel and serving to prevent debris from falling on the wheel and to preclude lateral movement of the bracket if one of the wheels should break.

11. The sectional scaffold as defined in claim 1 wherein each of said trackways comprises an l-beam having spaced flanges and a connecting web defining oppositely facing U- shaped channels, and said means mounting said brackets comprises two vertically spaced pairs of wheels, the wheels of each pair being rotatable about a common horizontal axis with one wheel being disposed in each of said U-shaped channels for engagement with at least one of said flanges.

12. The sectional scaffold as defined in claim 1 including a protective canopy overlying said platform means for protecting workmen and materials from the elements, said canopy extending outwardly beyond said platform means and adapted to overly the work area, and means removably mounting said canopy on said platform brackets for vertical movement therewith.

13. A platform for use with a sectional scaffold having upright sections and'connecting braces extending between the sections for moving workmen and materials vertically relative to a work area, said platform comprising a pair of spaced apart vertically extending trackways adapted to be connected to one side of two sections of the sectional scaffold outwardly of the connecting braces and each comprising a plurality of track sections each corresponding in length to the height of a scaffold section, platform means for supporting workmen and materials and comprising a pair of platform brackets and a supporting platform extending between and carried by said brackets,

14. The platform as defined in claim 13 wherein a clip is fixedly mounted at the top of each of said track sections, and said means for moving said platform means includes a cable hoist connected to each of said brackets and including a cable and cable hook carried by the outer end of the cable, said cable hook being releasably engaged by said clip.

15. The platform as defined in claim 13 wherein each of said trackways comprises an l-beam having spaced flanges and a connecting web defining oppositely facing U-shaped channels, and said means mounting said brackets on said trackways comprises a pair of wheels, one of said pair being disposed on 16. The platform as defined in claim further comprising releasable brake means comprising a plurality of vertically spaced abutments fixedly mounted on one of said trackway flanges, and a brake bar pivotally attached to each of said platform brackets and adapted to engage behind one of said abutments to preclude downward movement of said brackets along said trackways.

17. A platform for use with a sectional scaffold having upright sections and connecting braces extending between the sections for moving workmen and materials vertically relative to a work area, said platform comprising,

a pair of spaced apart vertically extending trackways adapted to be connected to one side of two sections of the sectional scaffold outwardly of the connecting bases, each of said trackways comprising an l-beam having spaced flanges and a connecting web defining oppositely facing U-shaped channels,

platform means for supporting workmen and materials and comprising a pair of platform brackets and a supporting platform extending between and carried by said brackets,

means mounting said brackets on said trackways for free, unobstructed vertical movement of said platform means relative to the scaffold, said means comprising a pair of wheels carried by each of said brackets, one of said pair being disposed in each of said U-shaped channels for engagement with at least one of said flanges,

means for moving said platform means vertically along said trackways, and

releasable brake means operatively connected between said brackets and said trackways for normally precluding downward movement of said brackets along said trackways.

18. A vertically adjustable platform support comprising a vertical trackway comprising a plurality of track sections arranged in longitudinal alignment,

a platform bracket,

means for slidably attaching said bracket to said trackway to permit relative vertical movement therebetween, cable means operatively connected between the top of one of said sections of said trackway and said platform bracket for supporting said bracket at a selected height,

hoist means for varying the effective length of said cable means to lift or lower said bracket, and

releasable brake means adapted to directly engage said trackway for preventing downward movement of said bracket along said trackway.

19. The platform support as defined in claim 18 wherein said brake means comprises a plurality of vertically spaced abutments fixedly mounted along the length of said trackway, and a brake bar pivotally attached to said bracket and adapted to engage behind one of said abutments to preclude downward movement of said bracket along said trackway.

20. The platform support as defined in claim 18 wherein said cable means comprises a clip fixedly mounted on said trackway, a cable hook releasably engaging said clip, and a cable connected between said cable hook and said platform bracket.

21. The platform support as defined in claim 18 wherein said trackway has a pair of oppositely directed U-shaped channels extending along the height thereof, and said means for slidably attaching said bracket to said beam includes a pair of rotatable wheels attached to said bracket, one of said pair being disposed in each of said channels for engagement with the walls thereof.

22. The platform support as defined in claim 21 wherein a horizontally extending member is attached to said bracket immediately above each of said wheels, said member partially entering the associated channel and serving to preclude lateral movement of the bracket if one of the wheels should break.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 3,610,368 Dated October S, 1971 Harold R. Johnson Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

IN THE CLAIMS:

Claim 2, column 5, line 64, after "defined" and before "claim" insert in Claim 13, column 6, line 64, after "brackets," insert means mounting said brackets on said trackways outwardly of said connecting braces for free, unobstructed vertical movement of said platform means relative to the scaffold, and

means operatively connected between one of the sections of each trackway and said platform brackets for moving said platform means vertically along said trackways.

Signed and sealed this 11th day of April 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents FORM PC3-1050 (10-69) USCOMM-DC 0D375-PBO w u.s. sovunmzm PRINTING orncz; n09 o-au-au 

1. In a sectional scaffold for supporting workmen and materials adjacent a work area compRising a plurality of substantially identical sections each comprising spaced uprights and at least one connecting member therebetween and some of which are adapted to be placed in parallel, upright relation to form a first level and others of which are adapted to be superposed above corresponding ones of the first and succeeding levels, and connecting braces extending between the sections of each level adjacent the uprights thereof; the improvement which comprises means for freely moving workmen and materials vertically relative to said scaffold sections without obstruction by said connecting braces and without the necessity of removing said braces, said means comprising means carried by one side of said scaffold sections adjacent the work area and defining at least two vertically extending trackways spaced outwardly of said connecting braces, platform means for supporting workmen and materials and comprising at least two platform brackets and a supporting platform extending between and carried by said brackets, means mounting said brackets on said trackways with said brackets and platform disposed outwardly of said connecting braces for free, unobstructed vertical movement of said platform means relative to said scaffold sections, and means operatively connected between said trackways adjacent the upper ends thereof and said platform brackets for moving said platform means vertically along said trackways.
 2. The sectional scaffold as defined claim 1 further comprising releasable brake means comprising a plurality of vertically spaced abutments fixedly mounted along each of said trackways, and a brake bar pivotally attached to each of said platform brackets and adapted to engage behind one of said abutments to preclude downward movement of said brackets along said trackways.
 3. The sectional scaffold as defined in claim 2 wherein said brake bar includes a forward arm directed diagonally downward toward said abutments and a rear arm directed away from said abutments, said forward arm being biased upwardly into engagement with said abutments.
 4. The sectional scaffold as defined in claim 1 wherein said means for moving said platform means comprises a pair of cable hoists connected to said platform brackets and each including a cable and a cable hook carried by the upper end of said cable, and a clip fixedly mounted on each of said trackways and being releasably engaged by said clip.
 5. The sectional scaffold as defined in claim 1 including means releasably connecting said trackways to one side of said scaffold sections.
 6. The sectional scaffold as defined in claim 5 wherein said trackway connecting means includes at least a pair of U-shaped brackets surrounding three sides of one upright of said scaffold sections and bolts mounted in said brackets and extending across the fourth side of said upright.
 7. The sectional scaffold as defined in claim 1 wherein each of said platform brackets includes an outwardly extending horizontal support member, and said supporting platform includes an end connecting bracket overlying and substantially surrounding each support member.
 8. The sectional scaffold as defined in claim 1 wherein each of said trackways comprises a plurality of vertically aligned track sections substantially corresponding in height to the height of a scaffold section.
 9. The sectional scaffold as defined in claim 1 wherein each of said trackways comprises an I-beam having spaced flanges and a connecting web defining oppositely facing U-shaped channels, and said means mounting said brackets on said trackways comprises a pair of wheels, one of said pair being disposed in each of said channels for engagement with at least one of said flanges.
 10. The sectional scaffold as defined in claim 9 wherein a horizontally extending member is attached to said bracket immediately above each of said wheels, said members partially entering the associated channel and serving to prevent debris from falling on the wheel and to precludE lateral movement of the bracket if one of the wheels should break.
 11. The sectional scaffold as defined in claim 1 wherein each of said trackways comprises an I-beam having spaced flanges and a connecting web defining oppositely facing U-shaped channels, and said means mounting said brackets comprises two vertically spaced pairs of wheels, the wheels of each pair being rotatable about a common horizontal axis with one wheel being disposed in each of said U-shaped channels for engagement with at least one of said flanges.
 12. The sectional scaffold as defined in claim 1 including a protective canopy overlying said platform means for protecting workmen and materials from the elements, said canopy extending outwardly beyond said platform means and adapted to overly the work area, and means removably mounting said canopy on said platform brackets for vertical movement therewith.
 13. A platform for use with a sectional scaffold having upright sections and connecting braces extending between the sections for moving workmen and materials vertically relative to a work area, said platform comprising a pair of spaced apart vertically extending trackways adapted to be connected to one side of two sections of the sectional scaffold outwardly of the connecting braces and each comprising a plurality of track sections each corresponding in length to the height of a scaffold section, platform means for supporting workmen and materials and comprising a pair of platform brackets and a supporting platform extending between and carried by said brackets,
 14. The platform as defined in claim 13 wherein a clip is fixedly mounted at the top of each of said track sections, and said means for moving said platform means includes a cable hoist connected to each of said brackets and including a cable and cable hook carried by the outer end of the cable, said cable hook being releasably engaged by said clip.
 15. The platform as defined in claim 13 wherein each of said trackways comprises an I-beam having spaced flanges and a connecting web defining oppositely facing U-shaped channels, and said means mounting said brackets on said trackways comprises a pair of wheels, one of said pair being disposed on each of said channels for engagement with at least one of said flanges.
 16. The platform as defined in claim 15 further comprising releasable brake means comprising a plurality of vertically spaced abutments fixedly mounted on one of said trackway flanges, and a brake bar pivotally attached to each of said platform brackets and adapted to engage behind one of said abutments to preclude downward movement of said brackets along said trackways.
 17. A platform for use with a sectional scaffold having upright sections and connecting braces extending between the sections for moving workmen and materials vertically relative to a work area, said platform comprising, a pair of spaced apart vertically extending trackways adapted to be connected to one side of two sections of the sectional scaffold outwardly of the connecting bases, each of said trackways comprising an I-beam having spaced flanges and a connecting web defining oppositely facing U-shaped channels, platform means for supporting workmen and materials and comprising a pair of platform brackets and a supporting platform extending between and carried by said brackets, means mounting said brackets on said trackways for free, unobstructed vertical movement of said platform means relative to the scaffold, said means comprising a pair of wheels carried by each of said brackets, one of said pair being disposed in each of said U-shaped channels for engagement with at least one of said flanges, means for moving said platform means vertically along said trackways, and releasable brake means operatively connected between said brackets and said trackways for normally precluding downward movement of said brackets along said trackways.
 18. A vertically adjustable platform support comprising a vertical trackway comprising a plurality of track sections arranged in longitudinal alignment, a platform bracket, means for slidably attaching said bracket to said trackway to permit relative vertical movement therebetween, cable means operatively connected between the top of one of said sections of said trackway and said platform bracket for supporting said bracket at a selected height, hoist means for varying the effective length of said cable means to lift or lower said bracket, and releasable brake means adapted to directly engage said trackway for preventing downward movement of said bracket along said trackway.
 19. The platform support as defined in claim 18 wherein said brake means comprises a plurality of vertically spaced abutments fixedly mounted along the length of said trackway, and a brake bar pivotally attached to said bracket and adapted to engage behind one of said abutments to preclude downward movement of said bracket along said trackway.
 20. The platform support as defined in claim 18 wherein said cable means comprises a clip fixedly mounted on said trackway, a cable hook releasably engaging said clip, and a cable connected between said cable hook and said platform bracket.
 21. The platform support as defined in claim 18 wherein said trackway has a pair of oppositely directed U-shaped channels extending along the height thereof, and said means for slidably attaching said bracket to said beam includes a pair of rotatable wheels attached to said bracket, one of said pair being disposed in each of said channels for engagement with the walls thereof.
 22. The platform support as defined in claim 21 wherein a horizontally extending member is attached to said bracket immediately above each of said wheels, said member partially entering the associated channel and serving to preclude lateral movement of the bracket if one of the wheels should break. 